Heat exchanger, in particular oil cooler

ABSTRACT

The present invention provides a heat exchanger including a flow duct for a coolant and a flow duct for a medium to be cooled, a cover on one side of the heat exchanger, and a thermostat valve operable to regulate temperature-dependent throughflow in one of the flow ducts, arranged on an inflow or outflow duct, and covered by the cover. A temperature sensor of the valve is arranged in a housing, which is fastened in proximity to the inflow or outflow duct so that one of the medium to be cooled and the coolant can flow around an outer side of the housing, with the temperature sensor on an inner side of the housing reacting to a local temperature and correspondingly regulating throughput of an other of the medium to be cooled and the coolant through the heat exchanger.

CROSS-REFERENCE TO RELATED APPLICATIONS

Priority is hereby claimed to German Patent Application No. DE 10 2007010 393.1, filed Mar. 3, 2007, the entire contents of which isincorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to a heat exchanger, such as an oil cooler.

SUMMARY

EP 0916816 B1 discloses a heat exchanger having several advantages. Inthe heat exchanger, a dome in the form of a cover, which, for example,serves for the introduction and distribution of the coolant, is situatedon one side. The heat exchanger is provided with a thermostat valvewhose temperature sensor extends into one of the inflow or outflowducts, in particular into inflow or outflow ducts which conduct themedium to be cooled, in particular oil. The valve element which iscontrolled by the temperature sensor and which controls the throughflowwith coolant is seated in the region of the coolant space closed off bythe cover. The coolant space is sealed off by means of seals withrespect to the one inflow or outflow duct for the other medium, with theseals being arranged between the thermostat valve and a holdingconnecting pipe for the latter. Such required seals are disadvantageous.They not only complicate the installation of the thermostat valve butcan also be sources of faults, can degrade in terms of their sealingaction or can lose the sealing action altogether. There is then the riskof the coolant being mixed with the other medium, which is to be cooled.This results in damage, in particular when using the heat exchanger inconnection with internal combustion engines, in particular of vehicles.

The present invention provides a heat exchanger, in particular an oilcooler, of the abovementioned type, in which seals of the type mentionedin the introduction can be dispensed with and the associatedsusceptibility to faults is eliminated.

The heat exchanger of the present invention can include a temperaturesensor of the thermostat valve that is not in direct contact with themedium to be cooled, and nevertheless can measure the temperature of themedium to be cooled by means of the housing which acts as a heatexchanger element, and as a function thereof, can control thethroughflow of the other medium, in particular coolant, with the coolantbeing reliably separated from the medium to be cooled, in particularoil, without the need for seals. The heat exchanger also has theadvantage of a very compact design. On account of seals not beingnecessary, costs are reduced. In addition, the thermostat valve can beeasily and simply assembled. The compact installation height of the heatexchanger does not have an adverse effect.

Further details and advantages of the invention and embodiments of theheat exchanger can be gathered from the following description, claims,and figures.

Other aspects of the invention will become apparent by consideration ofthe detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic, partially sectioned side view of a part of aheat exchanger with a section in the region of an inflow or outflow ductfor a coolant, as per a first exemplary embodiment.

FIG. 2 shows a section, similar to FIG. 1, of a part of a heat exchangeras per a second exemplary embodiment.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it isto be understood that the invention is not limited in its application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the following drawings.The invention is capable of other embodiments and of being practiced orof being carried out in various ways. Also, it is to be understood thatthe phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” or “having” and variations thereof herein ismeant to encompass the items listed thereafter and equivalents thereofas well as additional items. Unless specified or limited otherwise, theterms “mounted,” “connected,” “supported,” and “coupled” and variationsthereof are used broadly and encompass both direct and indirectmountings, connections, supports, and couplings. Further, “connected”and “coupled” are not restricted to physical or mechanical connectionsor couplings.

The drawings show, as an example for a heat exchanger 1, a heatexchanger, in particular in the design of an oil cooler, which isembodied for example as a housingless plate-type heat exchanger whichhas individual heat exchanger plates 2 and 3 which are placed one abovethe other, run horizontally, are joined together and form separatehorizontal flow ducts 10 and 11 which are delimited from one another.The flow ducts 10 are, for example, traversed by a coolant, inparticular cooling water. The flow ducts 11 are provided for the othermedium, for example oil, which is to be cooled. The relationships canhowever also be interchanged.

At the top and at the bottom in the drawings, the heat exchanger isclosed off, for example, by a cover plate or base plate 18 or the like.The heat exchanger 1 has inflow or outflow ducts which are connected tothe flow ducts 10, 11 and of which, in the drawings, only the inflow oroutflow ducts 9, 13 are visible on account of the local illustration,with it being possible for the visible duct to serve either for theinflow or the outflow of the coolant, in particular cooling water. Theinflow and outflow ducts 9, 13 extend through the plate stack and areconnected to the horizontal flow ducts 10 for the coolant. In acorresponding way, the inflow and outflow ducts (not shown) for theother medium, in particular oil, also extend through the plate stack,with said ducts which serve for the inlet and outlet of oil beingconnected to the horizontal flow ducts 11. The flow ducts 10 and 11 arearranged in an alternating manner with one above the other.

Arranged in the region of the upper cover plate 18 is a connecting pipe21 which can for example serve as an inlet for the coolant and which is,for example, assigned to the inflow duct 9. On account of thediagrammatic illustration, the outflow duct 13 for the coolant is notvisible, nor its outlet connecting pipe.

With regard to the basic design, the heat exchanger I correspondsapproximately to a design as can be seen from EP0916816 B1. In order toavoid unnecessary repetitions, reference is made to said disclosure,even to the extent that the heat exchanger can also be designed, insteadof the housingless design shown, for example, in such a way that theheat exchanger is surrounded by a housing which for example containsinflow or outflow ducts for the coolant, while flow ducts 11 for themedium, in particular oil, which is to be cooled are contained in theinterior of the housing. Heat exchangers of said type with an innerplate stack and an outer housing are also encompassed by the inventionand can be gathered for example from the above-stated publication.

The heat exchanger 1 which is embodied, for example, as an oil coolerhas, on the lower side in the drawing, a cover 4 which, in the exampleas per FIG. 1, is formed from an approximately pot-shaped orsubstantially convex dome 5. A thermostat valve 6 in the form of aregulating valve is also provided, which thermostat valve 6 is arrangedat the inflow or outflow duct 9, 13 which is covered by the cover 4, forexample, with the dome 5. The temperature-dependent flow through theheat exchanger in one of the flow ducts 10, 11 can be regulated by meansof said thermostat valve 6. For example, the flow through the flow ducts10 which conduct the coolant can be regulated in a temperature-dependentfashion, specifically as a function of the temperature of the othermedium, in particular oil.

Arranged at the lower region of the heat exchanger 1 in the drawings isa housing 40 which is embodied as a heat exchanger element. The housing40 is, for example, of pot-shaped design and is in direct contact with afacing plate, for example the base plate 18, of the heat exchanger 1 towhich the housing 40 is fixedly and sealingly fastened, for example, bysoldering, welding or the like. Here, the housing 40 overlaps the inflowor outflow duct 9, 13. A medium, in particular oil, can flow around theoutside 41 of the housing 40, which medium is situated in the space 42which is delimited by the cover 4, for example as per FIG. 1 with a dome5, and the plate 18. The housing 40 can be formed from aluminum orcopper, brass or the like.

The thermostat valve 6 is arranged in the lower region of the inflow oroutflow duct 9, 13, and in such a way here that its temperature sensor31 is situated within the housing 40 and, in this case on the inner side43 of the housing 40, reacts to the local temperature which correspondssubstantially or quite precisely to that of the one medium, inparticular oil, and on account thereof, correspondingly regulates thethroughput of the other medium, in particular coolant, through the heatexchanger 1. On account of this arrangement, the thermostat valve 6 isnot in contact with the medium to be cooled, in particular oil, as aresult of which there is no requirement for special seals for the mediumto be cooled, in particular oil. The housing 40 which is embodied as aheat exchanger element conducts the temperature of the medium to becooled, in particular oil, which is situated on the outer side to theinner side 43 and there, to the temperature sensor 31 of the thermostatvalve 6.

The temperature sensor 31 of the thermostat valve 6 can be in directheat-exchanging contact with the inner side 43 of the housing 40. Inthis case, the temperature of the medium to be cooled, in particularoil, in the space 42 is transmitted to the temperature sensor 31 bymeans of thermal conduction.

Instead or in addition, an intermediate space 44 can be formed betweenthe temperature sensor 31 of the thermostat valve 6 and the inner side43 of the housing 40. The intermediate space 42 can be connected to theinflow or outflow duct 9, 13 or, without a connection thereto, can befilled with the coolant or a heat transfer medium.

The housing 40 and/or the temperature sensor 31 of the thermostat valve6 can be provided with elements 45, 46, for example in the form ofprojections, fins or the like, which enlarge the thermal contact face ofthe housing 40 or temperature sensor 31. In the case of the housing 40,said elements 45 can be provided on its inner side 43 and/or outer side41. In this way, the thermal conduction from the medium to be cooled inthe space 42 to the temperature sensor 31 is further improved.

As is for example known from EP 0916816 B1, the thermostat valve 6, inthe case of the temperature sensor 31 being for example designed as anexpansion element thermostat in the interior of the housing, has anexpansion material which, in the event of a temperature increase,expands in terms of its volume and, in the event of a temperaturereduction, contracts again so as to reduce in volume. Inserted into theinterior of the housing and of the expansion material contained thereinis an actuating element in the form of a piston 26 which projects out ofthe housing and, in the event of a temperature increase, is pushed outof the housing of the temperature sensor 31. The piston 26 is connectedto a coaxial rod 32 which actuates a valve element 27, for example, inthe form of a valve plate. The valve element 27, which can be actuatedby the thermostat valve 6 and the passage 28 which is controlled by saidvalve element 27, are arranged in the interior of the inflow or outflowduct 9, 13 for the coolant. The housing 40 and the temperature sensor 31of the thermostat valve 6 are situated on the opposite side of the heatexchanger 1 from the valve element 27. The thermostat valve 6 is held inthe closed position illustrated in the drawing by means of a pressurespring 29 which acts on the valve element 27, and can be moved into anopen position in the event of the temperature sensor 31 being heatedwhen the other medium, in particular oil, in the space 42 has reached acorresponding temperature limit. This occurs in that the piston 26 ispushed out in the upward direction in the drawing, and as a result, therod 32 with the valve element 27 is moved upward in the drawing counterto the action of the pressure spring 29 and so as to open the passage28, so that a medium, in particular coolant, can flow into the inflowduct 9 or out of the outflow duct 13 and therefore the medium to becooled which is conducted in the flow ducts 11 can be cooled by thecoolant in the flow ducts 10. If the temperature of the medium to becooled falls below the response threshold of the temperature sensor 31of the thermostat valve 6, the expansion material in the housing of thepart 31 contracts so as to reduce in volume to such an extent that thepressure spring 29 can move the valve element 27 with the rod 32 and thepiston 26 in the downward direction in the drawing into the startingposition and therefore into the closed position.

In the case of an intermediate space 44 being formed between the innerside 43 and the temperature sensor 3 1, said intermediate space 44 canbe connected to the inflow or outflow duct 9, 13 for the coolant bymeans of small openings 47 which have only a small passage crosssection.

The described design of the heat exchanger has the advantage of acompact and simple design. It is possible to control the flow throughthe heat exchanger for example with coolant as a function of thetemperature of the other medium, for example oil, which is to be cooled,by means of a commercially available thermostat valve 6. Here, thethermostat valve 6 is not in contact with the medium to be cooled, forexample oil. Any seals or sealing materials are therefore not necessary.The temperature-dependent regulation is possible on account of thehousing 40 which is formed as a heat exchanger and which separates thetwo media, that is to say the medium to be cooled, in particular oil, onthe one hand and the coolant, in particular cooling water, on the otherhand from one another without the requirement for seals. The temperaturesensor 31 can be in direct heat-exchanging contact with the housing 40,with the elements 45, 46 increasing the heat conduction from the medium,for example oil, situated in the space 42 to the temperature sensor 31.It is likewise possible to provide an intermediate space 44 forincreasing the thermal conduction, which intermediate space 44 is filledfor example with a heat-exchanging medium or with coolant or is fed withcoolant via openings 47. Also advantageous is the simple design of theheat exchanger, which can in this way be of particularly compact design.The thermostat valve 6 can be inserted in a particularly simple mannerinto the heat exchanger 1.

While, in the first exemplary embodiment as per FIG. 1, the cover 4 hasan approximately cap-shaped dome 5 into which the housing 40 and thetemperature sensor 31 contained therein project at least predominantly,so that the one medium, for example oil, which is situated in theintermediate space 42 between the dome 5 and the housing 40, can flowaround the housing 40 at the outer side 41 of the latter, in the secondexemplary embodiment as per FIG. 2, the cover 4 which is provided on oneside of the heat exchanger is formed from a planar closure plate 7which, together with the plate 18 which runs at a distance therefrom andholds the housing 40, delimits a space 53 which conducts the medium tobe cooled, for example oil. The cover 4, specifically either with a dome5 corresponding to FIG. 1 or as a planar closure plate 7 as per FIG. 2,can be an integral component of an end plate of the heat exchanger 1.Depending on the design, the housing 40 can likewise be an integralcomponent of a plate 18, in particular of the final plate in the stack,of the heat exchanger.

In the second exemplary embodiment as per FIG. 2, the housing 40 and thetemperature sensor 31, which is contained therein, of the thermostatvalve 6 are contained, with the entire axial length, in the inflow oroutflow duct 9, 13 for the coolant. The temperature sensor 31 of thethermostat valve 6 is held completely by the housing 40. The housing 40and the temperature sensor 31 are therefore, as per FIG. 2, plungedaxially further into the inflow or outflow duct 9, 13, specifically asfar as possible as per FIG. 2. The housing 40 extends, with its end-sidebase 48, approximately within the plane of a plate 18 of the heatexchanger 1, for example, the final plate in the stack.

In contrast to FIG. 1, in the illustrated embodiment of FIG. 2, thehousing 40 is of double-walled design, in such a way that said housing40 is surrounded, at a distance from its outer side 41, by a casing 49which adjoins the housing 40 at the side 52 which faces away from and issituated opposite the base 48. The casing 49 extends from thereapproximately to the base 48 so as to form an outer annular space 50which is closed off with respect to the coolant and is open in thedirection of the space 53 which conducts the medium to be cooled, forexample oil.

The casing 49 is designed for the fastening of the housing 40 to theplate 18 of the heat exchanger. For this purpose, the casing 49 has aflange 51 at its free end which points downward in FIG. 2, by means ofwhich flange 51 the housing 40 is fastened, similarly to the firstexemplary embodiment as per FIG. 1, to the plate 18, for example thefinal plate in the stack, of the heat exchanger 1. The housing 40 formsan integral component with the casing 49. Otherwise, the same applies,corresponding to the above description for the first exemplaryembodiment as per FIG. 1, for the second exemplary embodiment as perFIG. 2. Since, in the second exemplary embodiment, the cover 4 isembodied as a planar closure plate 7 and no dome 5 is provided, theinstallation height of the heat exchanger 1 is yet further reduced,which heat exchanger is yet more compact as a result, with the overallpackage situation during installation for example in a motor vehiclebeing yet more favorable for said reasons. Further simplifications, inparticular savings, are given when the cover 4, in the design as perFIG. 1 or FIG. 2, is an integral component of an end plate, for examplea closure plate, of the heat exchanger 1. Further correspondingadvantages are given if the housing 40 is an integral constituent of aplate 18, in particular the final plate in the stack, of the heatexchanger 1.

In another exemplary embodiment which is not shown, the housing 40 andan inflow duct 9 or outflow duct 13 for the coolant form an integralcomponent. Here, the arrangement can be designed such that said integralcomponent is arranged close to or in the axial direction of an inflow oroutflow duct for the medium to be cooled, in particular oil, and isconnected by means of a duct to the coolant which is conducted in theheat exchanger 1. An integral component of said type is compact, withthe installation of said component not enlarging the installation heightof the heat exchanger and not having any adverse effect thereon. In theregion of the valve element 27 and of the associated valve seat in thepassage 28, it is possible to increase the throughput, generated whenthe valve element 27 is in the open position of the thermostat valve 6,of the coolant through the passage 28, and to reduce any pressure loss,in a conventional manner using structural means.

Various features and advantages of the invention are set forth in thefollowing claims.

1. A heat exchanger, in particular oil cooler, comprising: a flow ductfor a coolant and a flow duct for a medium to be cooled, the flow ductsbeing separated from one another and being penetrated by inflow andoutflow ducts; a cover on one side of the heat exchanger; and athermostat valve operable to regulate temperature-dependent throughflowin one of the flow ducts, arranged on an inflow or outflow duct, andcovered by the cover; wherein a temperature sensor of the thermostatvalve is arranged in a housing, which is fastened in proximity to theinflow or outflow duct in such a way that one of the medium to be cooledand the coolant can flow around an outer side of the housing, with thetemperature sensor of the thermostat valve on an inner side of thehousing reacting to a local temperature and correspondingly regulatingthroughput of an other of the medium to be cooled and the coolantthrough the heat exchanger.
 2. The heat exchanger according to claim 1,wherein the temperature sensor of the thermostat valve is in directheat-exchanging contact with the inner side of the housing.
 3. The heatexchanger according to claim 1, wherein an intermediate space is formedbetween the temperature sensor of the thermostat valve and the innerside of the housing.
 4. The heat exchanger according to claim 3, whereinthe intermediate space is at least partially filled with the coolant. 5.The heat exchanger according to claim 1, wherein the housing is providedwith elements which enlarge its thermal contact faces on inner and/orouter sides.
 6. The heat exchanger according to claim 1, wherein thetemperature sensor of the thermostat valve is provided with elementswhich enlarge its thermal contact face.
 7. The heat exchanger accordingto claim 5, wherein the elements are formed by projections, inparticular fins.
 8. The heat exchanger according to claim 6, wherein theelements are formed by projections, in particular fins.
 9. The heatexchanger according to claim 1, wherein the valve element and a passagecontrolled by the valve element are arranged in an interior of theinflow or outflow duct for the coolant.
 10. The heat exchanger accordingto claim 1, wherein the housing and the temperature sensor of thethermostat valve are arranged on a side of the heat exchanger oppositefrom the valve element.
 11. The heat exchanger according to claim 1,wherein a piston of the thermostat valve is connected by a rod to thevalve element.
 12. The heat exchanger according to claim 1, wherein thethermostat valve is maintained in a closed position by an elasticelement, and in the event of the temperature sensor being heated, can bemoved by the medium being cooled into an opening position.
 13. The heatexchanger according to claim 1, wherein the housing is of anapproximately pot-shaped design.
 14. The heat exchanger according toclaim 1, wherein the housing is a heat exchanger element and is formedfrom a material having relatively high thermal conductance.
 15. The heatexchanger according claim 1, wherein the housing is in contact with afacing plate of the heat exchanger and is fixedly and sealingly fastenedthereto.
 16. The heat exchanger according to claim 3, wherein theintermediate space is connected to the inflow or outflow duct for thecoolant by openings which have a small passage cross section.
 17. Theheat exchanger according to claim 1, wherein the cover is provided onone side of the heat exchanger and is formed from an approximatelypot-shaped dome, wherein the housing and the temperature sensor projectinto the dome, and wherein the medium to be cooled is situated in anintermediate space between the dome and the housing and can flow aroundthe housing along an outer side of the housing.
 18. The heat exchangeraccording to claim 1, wherein the temperature sensor of the thermostatvalve is held in its entirety by the housing.
 19. The heat exchangeraccording to claim 1, wherein the temperature sensor of the thermostatvalve is contained, with an entire axial length, in the inflow oroutflow duct for the coolant.
 20. The heat exchanger according to claim19, wherein the housing extends with an end-side base approximatelywithin a plane of a plate of the heat exchanger.
 21. The heat exchangeraccording to claim 20, wherein the housing is surrounded, at a distancefrom the outer side, by a casing which adjoins the housing at a sidesituated opposite the base of the housing and which extends from thereapproximately to the base so as to form an outer annular space which isclosed off with respect to the coolant and is open in the direction of aspace which conducts the medium to be cooled.
 22. The heat exchangeraccording to claim 21, wherein the casing is designed for the fasteningof the housing to a plate of the heat exchanger.
 23. The heat exchangeraccording to claim 22, wherein the casing has a flange at a free end,and is fastened by the flange to a plate of the heat exchanger.
 24. Theheat exchanger according to claim 21, wherein the housing forms anintegral component with the casing.
 25. The heat exchanger according toclaim 23, wherein the cover which is provided on one side of the heatexchanger is formed from a planar closure plate which, together with theplate which runs at a distance therefrom and holds the plate, delimits aspace which conducts the medium to be cooled.
 26. The heat exchangeraccording to claim 1, wherein the cover is an integral component of anend plate of the heat exchanger.
 27. The heat exchanger according toclaim 1, wherein the housing is an integral component of a final platein the stack of the heat exchanger.
 28. The heat exchanger according toclaim 1, wherein the housing and an inflow or outflow duct for thecoolant form an integral component.
 29. The heat exchanger according toclaim 28, wherein the integral component is arranged close to or in theaxial direction of the inflow or outflow duct for the medium to becooled.